Halarchaeum nitratireducens sp. nov., a moderately acidophilic haloarchaeon isolated from commercial sea salt Minegishi, Hiroaki and Yamauchi, Yuto and Echigo, Akinobu and Shimane, Yasuhiro and Kamekura, Masahiro and Itoh, Takashi and Ohkuma, Moriya and Usami, Ron,, 63, 4202-4206 (2013), doi = https://doi.org/10.1099/ijs.0.054668-0, publicationName = Microbiology Society, issn = 1466-5026, abstract= Two halophilic moderately acidophilic archaeal strains, MH1-136-2T and MH1-370-1 were isolated from commercial salt samples made from seawater in Japan and Indonesia, respectively. Cells of the two strains were pleomorphic and Gram-stain-negative. Strain MH1-136-2T was pink pigmented, while MH1-370-1 was orange–red pigmented. Strain MH1-136-2T was able to grow at 9–30 % (w/v) NaCl (with optimum, 21 % NaCl, w/v) at pH 4.5–6.2 (optimum, pH 5.2–5.5) and at 18–55 °C (optimum, 45 °C). Strain MH1-370-1 was able to grow at 12–30 % (w/v) NaCl (optimum, 18 %, w/v) at pH 4.2–6.0 (optimum, pH 5.2–5.5) and 20–50 °C (optimum, 45 °C). Strain MH1-136-2T required at least 1 mM Mg2+, while MH1-370-1 required at least 10 mM for growth. Both strains reduced nitrate and nitrite under aerobic conditions. The 16S rRNA gene sequences of strains MH1-136-2T and MH1-370-1 were identical, and the closest relative was Halarchaeum rubridurum MH1-16-3T with 98.3 % similarity. The level of DNA–DNA relatedness between these strains was 90.9 % and 92.4 % (reciprocally), while that between MH1-136-2T and Halarchaeum acidiphilum MH1-52-1T, Halarchaeum salinum MH1-34-1T and Halarchaeum rubridurum MH1-16-3T was 37.7 %, 44.3 % and 41.1 % (each an average), respectively. Based on the phenotypic, genotypic and phylogenetic analyses, it is proposed that the isolates represent a novel species of the genus Halarchaeum , for which the name Halarchaeum nitratireducens sp. nov. is proposed. The type strain is MH1-136-2T ( = JCM 16331T = CECT 7573T) isolated from solar salt produced in Japan., language=, type=